Both double-marker and triple-marker tests are critical prenatal tests that help monitor the baby's health and identify any potential risks during and after pregnancy.
Importance of Prenatal Care
Pre-birth or prenatal care begins the moment pregnancy is detected, and it's crucial to ensure a healthy birth. The care involves a group of checkups and tests, usually performed at different stages of the pregnancy, to ensure both the mother and baby remain healthy.
Prenatal also helps detect any potential risk factors that could affect the growth and development of the foetus and allows doctors to take proactive steps towards it.
Among the series of prenatal screening tests, double-marker and triple-marker tests are valuable tools, offering insights into the baby's genetic makeup and complications that may impact the baby's health after birth.
What is the Double Marker and Triple Marker Test?
Both double marker and triple marker tests are prenatal blood tests that screen genetic and chromosomal abnormalities in the developing foetus. A common differentiator of both tests is the time they are performed, their purpose and components measured.
Double Marker Test
Performed as part of early prenatal screening, unusually during the first trimester between 10 and 14 weeks, double marker blood test measures placental health through free beta-hCG (a pregnancy-related hormone) and PAPP-A (Pregnancy-Associated Plasma Protein-A).
Elevated or low levels of these markers can indicate chromosomal abnormalities and disorders. In a typical pregnancy, there are a set number of XX and XY chromosomes, which carry the genetic information. Normally, there are a total of 46 chromosomes in a human cell. However, in a few instances, there may be an extra copy or a missing chromosome, which can lead to trisomy.
Purpose
Doctors usually recommend a double marker test along with an NT scan, which is an ultrasound that evaluates the nuchal fold of the foetus for women above 35 years of age or those with a family history of chromosomal abnormalities. The tests detect trisomy of chromosome number 13, Trisomy 18 or Edward's syndrome and Trisomy 21 or Down Syndrome. Besides this, the double marker test also helps diagnose:
• Microcephaly
• Micrognathia
• Rocker bottom feet
• Short sternum and delays in neurological functions
• Umbilical hernia
Test Results
Available at a reasonable price, a double marker test can be ordered online from a reliable healthcare facility.
The range of 1:1000 or above is generally considered safe, with fewer risks of chromosomal abnormalities. And a ratio of 1:10 to 1:250 is considered high risk and screen positive.
The 1:10 implies that 1 in 10 pregnancies are at risk and require follow-up diagnostic tests. Detecting chromosomal abnormalities allows parents to prepare themselves for the challenges of raising a child with special needs.
Triple Marker Test
The triple marker test is an additional screening test performed between 15-20 weeks of the pregnancy and provides a broader analysis of the foetus's health and any potential health risk which may have not been detected in the first-trimester screening.
The test screens for levels of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3), which calculate the probability of chromosomal abnormalities, and neural tube defects such as spina bifida and anencephaly, and other congenital disabilities in the baby.
Similar to the double marker test, triple marker is recommended for mothers above 35 years of age or with a family history of congenital disabilities. But also to those who,
• Have diabetes or use medicines to maintain insulin.
• Is highly exposed to radiation.
• Had a severe case of viral infection during pregnancy.
Test Results
A normal range for the triple marker test is between 0.5 and 2.5 mIU/mL.
Best Course of Action
Both triple marker and double marker tests are screening tools, but their results depend on several factors, including the mother's age, medical history, ethnicity and body weight and the results may vary.
Therefore, it's always recommended to consult a healthcare provider to better understand the health scenario and plan.
